1. Field of the Invention
This invention relates to a manually operated throttle control and, more particularly, to a manually operated throttle control secured to a gearshift lever to be used separately from a foot operated throttle control.
2. Description of the Prior Art
The idea or concept of a manually operated throttle control is not new. In some cases, such as disclosed in U.S. Pat. No. 1,716,814, a manually operated throttle control was connected to a foot operated throttle control or accelerator. The throttle control is secured to the gearshift lever in the '814 patent. The apparatus includes mechanical linkage through a system of levers and is actuated by lifting up a handle in a movement substantially parallel to the longitudinal axis of the gearshift rod.
Another type of manually operated throttle control is disclosed in U.S. Pat. No. 1,815,772. This apparatus is also generally a rod linkage connected to the same rod that the foot controlled throttle or accelerator pedal is connected to. The mechanical linkage is actuated by a lever which is gripped by the hand adjacent the top of the gearshift lever.
A cable operated throttle control is disclosed in U.S. Pat. No. 1,838,289. As in the previous two patents, the cable is linked to the accelerator pedal or foot operated throttle control. The apparatus in the '289 patent discloses a ratchet stop for maintaining the throttle in the appropriate, desired position. The ratchet stop presents a potential safety problem in that the apparatus may not be easily disconnected and harm may result therefrom.
Another example of cable linkage is disclosed in U.S. Pat. No. 1,959,881. As with the prior art patents, the '881 patent discloses linkage directly connected with the accelerator pedal. The cable is manually actuated through a mechanical linkage system built into a portion of the gearshift lever.
In both the '814 and '289 patents, the throttle actuation is by vertical movement along the longitudinal axis of the gearshift lever. In the '772 patent and the '881 patent the actuation of the throttle is by a pivoting action, although the '881 pivoting action is not direct, but rather is through a mechanical linkage. In all four of the patents, the mechanical linkage is connected directly to the single throttle linkage extending from the carburetor to the foot pedal of the vehicle. It will be noted that in the '881 patent, the throttle linkage must be pushed, rather than pulled, by the user. In the '772 patent, the lever must be squeezed in order to operate through a mechanical linkage system of rods and pivots.
The '289 patent includes ratchet stops which present a safety problem. Moreover, the motion of pulling axially may be difficult to accomplish, particularly with the hands involved in shifting gears. That is, in order to exert an axial pull along the longitudinal axis of the gearshift lever, the gearshift lever must be held in a particular manner. Similarly, the '814 patent requires also the grasping of the gearshift lever in a certain manner in order to exert an axial pull of the throttle control linkage. The throttle control and the gearshift lever in the '814 patent require a piston grip type hold on both the gearshift lever and the throttle control in order to operate. It would appear to be difficult to shift gears on the '814 apparatus without at the same time affecting in some manner the throttle control due to the particular design and arrangement of the apparatus.
Undoubtedly, the particular design embodied in the patents discussed above resulted from a specific need, which was probably accomplished by the particular apparatus. Another, and different, need which requires different apparatus, is satisfied by the apparatus of the present invention.
Four-wheel drive vehicles have been gaining in popularity in recent years. They allow the operators of the vehicles to have access to geographic areas not possible hitherto due to lack of roads, rough terrain, and other problems. However, one of the limitations imposed on fourwheel drive vehicles is their ability to maneuver, such as on a steep incline, or when towing a trailer, or when maneuvering on switchbacks, due to problems of controlling engine speed and operating the brake and the clutch at the same time. The obvious solution is to enable the operator to control engine speed manually while operating the brake and the clutch with both feet. Logically, the location most favorable for manual operation of engine speed (throttle control) is on the gearshift lever, since it is very likely that the gearshift may be operated at the same time the clutch and brake are required.
The normal emergency brake lever is of no, or little, value during such times due to the location of the emergency brake and its holding capacity. The emergency brake is typically actuated by hand, thus requiring the operator to release his control on either the steering wheel or the gearshift lever for actuation of the emergency brake. Moreover, the emergency brake typically is connected to only the rear wheels and applies only limited force through mechanical linkage.
In response to the problems and needs discussed above, it is desirable to provide a manually actuated throttle linkage which may, but need not, be operated in conjunction with the shifting of gears, and which is responsive to slight, convenient finger pressure but yet will not interfere with normal operation of the gearshift apparatus.